This issue was finally resolved by focusing on the computers and/or printers announcing the multicast dns advertisement of available printers. When you need to disable printers from appearing in the "Nearby Printers" list, locate the machines advertising services and shut down the announcement; more below.
If you are not certain which computer or printer is advertising its services, download a bonjour browser app first; I used:
http://www.macupdate.com/app/mac/13388/bonjour-browser
With that application launched, you can navigate down the browser list by expanding nodes and see which machines IP addresses are advertising an available printer service.
Next, the remaining how-to requires you to know which machines IP addresses correspond with the machines.
For Mac desktops, laptops, and servers that appear in the list, physically go to those devices and navigate the machine's System Preferences > Print & Fax control panel and for each printer, make sure that the checkbox "Share this printer on the network" is unselected. Note that--if you already have not guessed--this will disable the ability for another machine to navigate and print to a shared printer on that machine. If, by necessity, that machine must share that printer, but you do not want its sharing to be discoverable, you must disable that machines multicast dns broadcast.
Machines that must share printer queues where you would like to disable the machines multicast dns bonjour 'Printer Available' broadcast advertisement packets to remote machines in order to prevent them from showing up in Nearby Printer listings, you should follow the tutorial here:
http://support.apple.com/kb/HT3789?viewlocale=en_US
or here:
http://blog.tsunanet.net/2010/02/how-to-disable-bonjour-on-osx-106-snow.html
Lastly, nearby printers listings will pick up the 'Printer Available' dns bonjour advertisements of the printers internal network configurations as well. To disable those, most modern network printers have built-in web administration control panels available to you from a web browser. For example, open up safari, type http://the-numeric-IP-address-of-your-printer-here
and then select the enter key. You should then be able to navigate to the Networking configuration web page available from the printers web administration interface and disable bonjour/multicast print settings. Most HP network printer installations for example, only need port 9100 and IPP sevices enabled for typical Macintosh and Windows network printing services to work...and all other Miscellaneous printer services may usually be disabled. If you are not the network administrator, check with them to confirm that no other special network applications require additional non-typical print services.
That's it! Once you have disabled or hidden the print services advertisements, the machines on the local network subnet will no longer show Nearby Printers.
Hopes this helps someone!
Best,
TechieChica